<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <!-- <meta name="viewport" content="width=device-width, initial-scale=1.0"> -->
    <meta name="viewport" content="width=device-width, initial-scale=1.0,maximum-scale=1,minimum-scale=1,user-scalable=no">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .box {
            height: 50px;
            width: 800px;
            border: 1px solid #000;
            text-align: center;
            margin: 50px auto;
            position: relative;
        }

        .h1 {

            display: block;
            float: left;
            width: 49.7%;
            /* float: left; */
        }

        .h2 {
            width: 49.7%;
            float: right;
            display: block;
            /* float: right; */
        }

        .h41 {
            position: absolute;
            left: 25%;
            width: 66px;
            height: 45px;
            line-height: 48px;
            border-bottom: 3px solid red;
        }
        h4:hover{
             border-bottom: 3px solid red;
        }
        .h42{
            position: absolute;
            right: 25%;
            width: 66px;
            height: 45px;
            line-height: 48px;
        }
    </style>
</head>

<body>
    <div class='box' id=''>
        <a class="h1">
            <h4 class="h41">黑人</h4>
        </a>
        <a class="h2">
            <h4 class="h42">牙膏</h4>
        </a>
    </div>
</body>

</html>